Now, Elizabeth Wurtzel thinks that the photograph she used for the cover of Bitch may not have been a great idea. "I had a lot of trouble with the cover of Bitch. The publisher liked it, and I thought, fine. But had I been more lucid at the time I might have thought it's not so good. It got in the way of the content of the book. But I hope that some time in the future I'll look back and it will seem like a cool gesture."

That's the way Wurtzel talks - hopping along, apparently wondering as she goes whether she has done or said the right thing. She smiles and laughs a lot, a bright, shiny woman who looks younger than her 32 years, with her glossy, cerise lipstick and long, blonde, highlighted hair. Although she complains of jetlag, she seems energetic and eager, happy to rattle along about anything, from the intimate details of her life to the Philippine hostage crisis.

Is she finally cured of the terrible depression that inspired Prozac Nation? "No, I'm not," she says. "That's the sad part. I'm still on medication. Maybe I should learn to lie about this. Because they're making the movie of it now, and of course they are giving it a happy ending, and it would be so much more satisfying to say it did have a happy ending, nothing bad happened after that. But life isn't like that."

In Prozac Nation, Wurtzel often seems to blame her parents for her depression. As the only child of divorced parents, she had to bear her mother's intense expectations and her father's total lack of interest. Wurtzel's mother, perhaps understandably, hasn't read the book. "She doesn't even read my articles," Wurtzel says, sadly. "She doesn't even read articles about me." Then she shifts ground. "I wrote a piece recently about my addiction to Ritalin, and I rang her and warned her not to read it because it would upset her. She did and she called me and said she was so sorry, that she had no idea what I'd been through and it was a miracle I was still alive and doing so well. That meant so much."

Wurtzel's relationship with her father has a lot less going for it. In Prozac Nation she recalls, as a child, trying to prise his eyes open as he slept through her brief visits to him. Now, she hasn't had any contact with him since 1990, although he made a misplaced effort to see her two years ago when she was doing a reading. "He just showed up. I'm working. It's not a good time to surprise someone - it's unfair. I did my reading and asked someone to ask him to leave during the signing. It's not like my desire not to see him is totally random. If you had a father like mine, there's a good chance you wouldn't want to see him either."

Prozac Nation was published in 1994, at first to a mixed response. "I had some terrible reviews," Wurtzel remembers. "Some people's reactions to the book were like people's reactions to a depressed person - they felt impatient, that I was being self-indulgent. I was heartbroken. But then I realised that all these people out there really liked it." Certainly, the book touched a chord with young depressives, but the success that ensued was, in Wurtzel's vulnerable mental state, rather too much to handle. "I was flattered, I was pleased, I was elated, I was astonished," she says eagerly. "But I ended up with a cosmic drug problem."

That led to a long period of drug abuse, during which Wurtzel still managed to write Bitch. "It was Ritalin abuse, which is speed," she explains. "That can help you focus. But on speed you can water a plant for three days, you get so obsessed. It is a book written on drugs. And it is better to write sober." The book's subtitle is, "In Praise of Difficult Women", but rather than celebrating forceful females, it looks darkly into the lives of victims such as Amy Fisher, who killed her abusive lover's wife, and Nicole Brown Simpson, OJ's doomed partner. There's nothing feelgood; the chapter about Amy Fisher ends up by suggesting that suicide would have been her only way into freedom, while the chapter on Nicole Brown argues that she must have been complicit with her husband's violence.

Wurtzel admits that it's a mixed-up book, but she loves it partly for what she went through writing it. "I think it saved my life. I wanted to write about crazy behaviour and praise it but I ended up thinking, this is all a nightmare. It made me think again about how I could keep my life from turning into this kind of disaster."

It may seem pretty amazing that Wurtzel, with all her problems, is setting herself up as a lifestyle guru with her new book, The Bitch Rules. It reads like a spoof of all those terrible American self-help books, and parts of it are certainly pretty funny. "Don't clear the table at a dinner party unless the men get up to help too", runs one chapter heading. "Eat dessert".

But for Wurtzel there is something serious in her advice. "I went into drug addiction recovery after writing Bitch," she says. "The idea behind those programmes is: change your behaviour and you'll change your life. It made me realise there are things you can do to make your life better."

Although most writers of rule books hold up their own perfect lives as a template, Wurtzel confesses that she still hasn't got her own world sorted. She doesn't like where she lives. "I can't stand my apartment," she tells me. And her recent relationship history sounds like a disaster area. "The thing I have trouble with is getting the stuff with men right," she says. "I just got out of something that looked very promising. But he is a junkie, and not doing well in staying clean. Before him I was involved with someone I met when I was in hospital. But he went back to drinking. I really fell in love with him. I think I still am."

Would you buy lifestyle advice from her? Maybe you will, since she packages it up with an attractive spin, and a lot of The Bitch Rules is a good antidote to contemporary marriage obsessions. "Do not view the years between college and marriage as one long preamble to real life," Wurtzel orders. "Learn to love other things than boys." And the optimism that she expresses in it has clearly been salvaged from dark places. Because despite all her desperate times, Wurtzel says she has faith that things will work out for her one day. "In general it does work out for people, sooner or later," she says dreamily. "You have to be willing to accept the good things that come your way. Sometimes I have a hard time doing that."